A network analyzer is calibrated in order to eliminate measurement errors. However, there are cases where this calibration is not completed correctly because of problems with the stability of the network analyzer, the malfunction of standards, and other problems. Therefore, it is necessary to verify the result of the calibration.
Testing devices with a known S parameter (Scattering parameter) represent the recommended method for verifying calibration in the prior art. Standard sets for verification referred to as verification kits, standards other than calibration standards used for calibration, and other devices are used in actual calibration (for instance, refer to User's and Service Guide, Agilent Technologies, 85053B 3.5 mm Verification Kit,” Agilent Technologies, January, 2002, p. 4-1 through 4-18). Moreover, there are also cases where standards used in calibration are re-used (for instance, refer to U.S. Pat. No. 5,332,974).
Verification of calibration by the prior art poses the following problems. For instance, it is difficult to handle the verification kit of the verification method that employs a verification kit and therefore, there tend to be mistakes in the calibration verification. Furthermore, this verification method requires its own specific verification kit. If the verification method that uses standards other than calibration standards is employed, verification results are sometimes obtained that indicate that the calibration was successful even though there were actual mistakes in the verification when the other standards have properties similar to calibration standards. Furthermore, this verification method requires standards other than calibration standards. When the verification method whereby calibration standards are re-used is employed, there can be times when verification results indicating that the calibration was successful are obtained even though there were actually errors in the calibration. Moreover, the above-mentioned conventional verification methods require additional measurements for verification independent of calibration. These problems become more severe with an increase in the number of ports, making verification of calibration difficult.
Therefore, the object of the present invention is to solve these problems. That is, the object of the present invention is to provide a method for verifying full n-port calibration that is easier to use than the prior art and does not require additional standards or additional measurement.